Prior multilayer optical films use alternate layers of a polymer based a crystalline polyester and another polymer. This uses a phenomenon in which rays are reflected through a constructive interference generated at an interface of materials having different refractive indexes with each other. Especially, among multilayer optical films, polyester is used as a useful material for a first component of a polarizer film, and this is because it has high double refractive index in the case of a naphthalene dicarboxylate polyester among polyesters. In addition, the characteristics of the polymer based polyester are determined by monomer materials used during manufacturing the polymers, and therefore, there are advantages of being able to easily adjust the refractive index. Also, when compatibility of a second component with the first component drops, peeling off of films may occur, but this is because a variety of copolymerization of the polymer based polyester is possible, and selecting a material that may satisfy optical characteristics while preventing peeling off of the first component and the second component is easily carried out.
Likewise, regarding the multilayer optical films, until now, development of simplification of methods for manufacturing the multilayer optical films and improvement of optical characteristics of materials have been carried out, and also in Korea patent registration No. 10-0364029, regarding a multilayer polymer film comprising multiple alternate layer agents of crystalline naphthalene dicarboxylate ester and another selected polymer is disclosed. But, different from before, along with recent trends of slimness of display devices, problems of heat generating from devices are becoming issues, and importance of developing materials having stability is coming to the fore.